JASON STEARNS is the author of Dancing in the Glory of Monsters: The Collapse of the Congo and the Great War of Africa and Director of the Usalama Project, a research program on Congolese armed groups at the Rift Valley Institute. Follow him on Twitter @jasonkstearns.

In the last week of October, the Democratic Republic of the Congo became a world turned on its head. The Congolese army, better known for its human rights abuses than for its battlefield efficiency, finally steamrolled through the positions of the so-called March 23 Movement, or the M23, breaking the deadlock with the rebels they had been fighting since April 2012. The UN peacekeeping mission there, long criticized for inaction, put attack helicopters up in the air and ordered its soldiers to use deadly force to back the Congolese army’s offensive. And the Rwandan government, which had intermittently supported armed groups in eastern Congo for the past 17 years, suddenly cut off its aid.

Within a week, the M23 officially disbanded, and its leaders fled to neighboring Uganda and Rwanda. It is hard to overstate how historic a development that is. For the first time since 1997, Rwanda has no military footprint in eastern Congo and the Congolese government has been able to defeat a serious armed rebellion. In recent days, villagers have laid down palm fronds and fabric for the country’s victorious army -- a far cry from the suspicion and derision it usually receives.

The biggest reason for the sudden turn in events is that Rwanda pulled the plug. As I wrote recently in “Helping Congo Help Itself”[1] (Foreign Affairs, September/October 2013[2]), the Rwandan government has long deemed it necessary to have an armed ally across the border to protect its interests in the Congolese highlands. The Rwandan army backed the Alliance of Democratic Forces for the Liberation of the Congo from 1996 to 1998, the Congolese Rally for Democracy from 1998 to 2003, the National Congress for the Defense of the People from 2004 to 2009, and the M23 for the past 19 months.

But as the Rwandan government faced heightened criticism for helping the rebels, especially on the part of the U.S. government, it changed course. Although the Rwandan army was still providing support in August, when the Congolese army launched its offensive on October 25, “the Rwandans